It is known to combine various woven, knit or nonwoven fabrics with plastic sheets or resin layers or to impregnate them with resins to form composite sheets primarily intended for use in thermoforming and molding processes. For example, U.S. Pat. No. 5,075,142, to Zafiroglu and Japanese patent application publications 63-111050 and 63-162238 disclose such composite sheets. U.S. Pat. No. 4,298,643, to Miyagawa et al. discloses a particular fabric having an exposed pile layer, the back of the fabric being bonded or laminated to a thermoplastic sheet. Such composites, however, are not as suitable for use in certain abrasive resistant articles, such as athletic shoe parts, luggage corners and surface layers, protective work clothes, certain heavy-duty sacks and the like.
Pile fabrics, such as velvets, velours, terry cloths, moquettes, tufted fabrics, and the like, each have a surface layer in which fibers are generally vertical to the surface of the fabric. Certain stitch-bonded fabrics, in which a fibrous layer is contracted and buckled by means of elastic threads attached to the fibrous layer to form a layer of pile-like groups of fibers, are disclosed by U.S. Pat. Nos. 4,773,238 and 4,876,128 to Zafiroglu. Needle-punched fabrics are also known to have fibers forced into the direction normal to the sheet by the needles. Some of these pile-like fabrics are incorporated into composite sheets. As one example, coarse carpet fibers are needle-punched into felts and stabilized with adhesive applied on their back-face, to be used as trunk liners, low-cost floor coverings and other similar uses, with the adhesive-coated back face being laid down and the upper face used as a carpet like surface. In another example, in which the coated face is used facing up as an abrasion resistant surface, Japanese laid-open patent applications 64-85614 and 64-85615 disclose a floor mat, which includes a tufted-monofilament pile, having an 8 mm height and a 0.08 g/cm3 pile fiber concentration, onto which a rubber resin is sprayed. The combination of the pile fiber and resin comprises about 38% by weight of resin and has an average density of only 0.13 g/cm3. Higher density of fibers, higher weight of resin per unit volume, and higher resistance to planar and compression deformation were found to be needed by subsequent art to achieve high resistance to abrasion.
U.S. Pat. No. 6,063,473 entitled “Abrasion-Resistant Composite Sheet” to Zafiroglu discloses denser, more stable and relatively thin pile or pile-like fabrics immobilized with resin to make abrasion-resistant composite sheet. The sheet comprises an upper outer surface, a lower surface, and a planar fibrous network located between and substantially parallel to the upper and lower surfaces. This composite sheet further comprises pile-like fibers that loop through the planar fibrous network and protrude generally perpendicularly from the planar fibrous network extending to the upper outer surface of the composite sheet, and a resin that immobilizes the pile-like fibers in a position generally vertical to the planar fibrous network. The resin extends through the stratum of pile-like fibers from the upper outer surface to a depth of at least 0.5 mm, and more preferably throughout the composite. The composite has a planar stretchability of no greater than 25%, and a vertical compressibility of no more than 25%. Typically, the composite sheet comprises in the range of 30 to 90 percent resin, preferably at least 50% and most preferably at least 70%, based on the total weight of the composite. Typically, the composite sheet exhibits a 40-grit Wyzenbeek abrasion wear of no more than 50 microns per 1000 cycles. This composite is relatively expensive and stiff due to the relatively high resin density within a relatively thick layer which is required to stabilize the vertical orientation of the fibers within the face layer, and to limit the extensibility and compressibility of the sheet.
United States published patent application 2004/0191470 A1, Ser. No. 10/403,208 describes a fibrous product wherein the fibers of a web are positioned in a pile-like configuration normal to the plane of the web, and wherein the web contains uniformly distributed low-melt resin or adhesive, which is activated “in-situ”. The resin may be in the form of binder fibers, co-spun low-melt/high-melt fibers, or powders. A densified resin-fiber rich skin is formed on the pile-like surface by applying heat and pressure, with the lower portions of the sheet being interbonded. This technique improves the technology of the '473 patent by combining abrasion resistance, softness, dyeability and moldability.
However, there remains a need for composites that concentrate the adhesive or resin at the abrasion-resisting face for optimum softness and cost, and allow for the construction of thicker or multi-layer structures that, in addition to abrasion resistance, can provide secondary functions such as cushion, comfort, fluid absorption, moisture transport, and the like: